Earth Sciences Commons^™

Fayetteville And Imo Shales: Punctuated Upper Mississippian Shallowing Upward Sequence, Southern Ozark Region, Northern Arkansas, Joshua Stevens

Graduate Theses and Dissertations

The late Mississippian lithostratigraphic succession in the southern Ozark region, northern Arkansas, include, in ascending order, the Meramecan Moorefield Shale, Batesville Sandstone (with Hindsville Member); Chesterian Fayetteville Shale and Pitkin Limestone (with Imo Member). This interval is now interpreted as a single transgressive-regressive, unconformity-bounded, eustatic, third order cycle (Stevens and Manger, 2018). The Moorefield lowstand wedge is bound by a basal unconformity and succeeded by the transgressive Batesville Sandstone with its Hindsville Member. This succession reflects accretionary deposition along strike of the rising strand line, likely as a barrier island system, as its equivalents are shale (basinward) and limestone (laterally …

Studies Of Quaternary Depositional Systems Of The Coastal Plain And Inner Continental Shelf Along The Georgia Bight: South Carolina And Georgia, U.S.A., Joshua H. Long

Electronic Theses and Dissertations

The Quaternary stratigraphy of the continental shelf offshore of South Carolina consists of stratigraphic units deposited in coastal plain, shallow marine, and shelfal environments bound by composite erosional surfaces that developed in response to numerous glacioeustatic cycles and overprinted by regional uplift. These units are commonly distributed laterally rather than stacked vertically, a function of the long-term, low shelf gradient and the resulting lack of accommodation. This study integrates high-resolution geological and geophysical data sets acquired offshore and onshore with existing data onshore into a comprehensive conceptual model describing the Quaternary geologic evolution of the coastal plain and continental shelf …

Integrated Studies Of Intracontinental Deformation In The Interior Western Usa, Cretaceous To Recent, Jacob Oliver Thacker

Earth and Planetary Sciences ETDs

The advent of plate tectonic theory satisfactorily explained a number of deformation belts around the world. However intracontinental deformation (deformation inboard of a plate margin) remains poorly understood in plate tectonic models. In order to further our understanding of intracontinental tectonics and its effects, this dissertation examines paleotectonic and neotectonic settings within the interior western USA.

Chapter 1 focuses on late Miocene–Recent deformation inboard of the San Andreas plate margin fault and its role on the integration history of the lower Colorado River. The neotectonic analysis included geometric and kinematic fault data collected in key geologic units to characterize the …

The Stratigraphy Of The Oligocene-Lower Miocene Deposits Of Southern Ukraine, Yuliia V. Vernyhorova, Tamara S. Ryabokon

Turkish Journal of Earth Sciences

Lithostratigraphic units (formation, strata, and beds) and regional stages of the Oligocene-lower Miocene succession of southern Ukraine are described based on the results of comprehensive lithological and paleontological data analysis. The historical perspective on the stratigraphical investigations of the Maikop Group in the Crimean and Kerch Peninsulas and their equivalents in the broader Peri-Black Sea Region were also integrated in this overview. Moreover, a correlation was established between the locally defined regional stages and specific stratigraphic horizons of southern Ukraine, the global Oligocene and Miocene stages (defined by the International Stratigraphic Chart), and the stages of the Eastern Paratethys. The …

Paleoecological Successions From Shallow-Marine Depositional Environments In Upper Silurian Carbonate Rocks Of Blair County, Pennsylvania, Shadya El-Ashkar

Graduate Theses, Dissertations, and Problem Reports (ETD)

Studies of paleoenvironment and paleoecology are important for investigating relationships between the different environmental and biological variables that influenced biodiversification patterns during the Silurian Period. The mixed carbonate and siliciclastic rocks of the Bloomsburg and Mifflintown Formations in central Pennsylvania represent transitions between carbonate ramp and deltaic settings. The goal of this study was to assess changes in depositional environment and paleoecology of an undescribed Bloomsburg/Mifflintown locality in Bellwood, Pennsylvania. In central Pennsylvania, the interfingered relationship of mixed carbonate and siliciclastic mudstones of the Mifflintown Formation with red fine-grained sandstones and shales of the Bloomsburg Formation presented challenges for deciphering …

Process Based Analysis Of Fluvial Stratigraphic Record: Middle Pennsylvanian Allegheny Formation, North-Central Wv, Oluwasegun O. Abatan

Graduate Theses, Dissertations, and Problem Reports (ETD)

Fluvial deposits represent some of the best hydrocarbon reservoirs, but the quality of fluvial reservoirs varies depending on the reservoir architecture, which is controlled by allogenic and autogenic processes. Allogenic controls, including paleoclimate, tectonics, and glacio-eustasy, have long been debated as dominant controls in the deposition of fluvial strata. However, recent research has questioned the validity of this cyclicity and may indicate major influence from autogenic controls. To further investigate allogenic controls on stratal order, I analyzed the facies architecture, geomorphology, paleohydrology, and the stratigraphic framework of the Middle Pennsylvanian Allegheny Formation (MPAF), a fluvial depositional system in the Appalachian …

Fluvial Interactions Of The Jurassic Salt Wash Member Of The Morrison Formation With The Gypsum Valley Salt Diapir, Co, Clair Henry Bailey

Open Access Theses & Dissertations

Gypsum Valley diapir in Gypsum Valley Colorado is an ideal location to investigate the interaction between a fluvial system and a diapir going through late stage collapse and rise. The outcrop exposures in Gypsum Valley allow for the analysis in changes of the fluvial system of the Salt Wash Member of the Morrison Formation as it gets redirected by the salt wall and deposits sediment on top of, on the margins, and in the Disappointment and Dry Creek minibasins. Previous work has focused on understanding and predicting how fluvial systems react when they encounter a salt diapir, but all the …

Major Lower Paleozoic Horizons Of The Southern Illinois Basin, John B. Hickman

Report of Investigations--KGS

The geology exposed at the surface in the southern Illinois Basin has been mapped in great detail by countless workers over the past century. With the exception of limited and scattered exposures in incised river valleys, the oldest rocks exposed outside of the Jessamine, Nashville, and Ozark Domes surrounding the Illinois Basin are Mississippian in age. Extensive deposits of Cambrian–Devonian sediments occur in the subsurface above crystalline basement in this region, however. All available data for the region were analyzed to produce a single, comprehensive set of interpretations. The data used in this study include 1:24,000-scale geologic quadrangle maps, oil …

Investigation Of Subsurface Stratigraphy And Groundwater Dynamics In The Mississippi River Delta, An Li

LSU Doctoral Dissertations

The Mississippi River Delta (MRD) is socioeconomically important to the state of Louisiana and the United States. Various types of land-water system data have been collected in the MRD. However, very few efforts have been made to utilize these datasets in modeling regional stratigraphy and groundwater dynamics in the MRD, especially for the upper 50 m of the depth. In this interval of depth, the Mississippi River and surrounding interdistributary bays intensively interact with the groundwater system. The lack of knowledge in regional stratigraphy and groundwater dynamics hinder an understanding of how hydrogeological setting affects processes such as surface-groundwater interaction, …

Geochemical Analysis Of The Chinchín Formation In Southern Ecuador, Katherine Ludwig

Celebration of Learning

The subduction of the Nazca Plate under the South American Plate has led to the uplift of the majority of the Andes Mountains, but in Ecuador, the Nazca Plate subducts underneath the North Andes Plate, which then collides with the South American Plate. This tectonic setting has formed two parallel mountain chains as well as a complex series of basins between them. However, the formations that make up these basins are poorly understood. This study focuses on the Chinchín Formation, an ~3.5 km thick, volcanic formation that serves as the bedrock of the Quingeo Basin in southern Ecuador. This study …

Assessing Paleoenvironmental And Geomorphic Variability In Relationship To Paleoindian Site Burial; Centennial Valley, Montana, Hillary A. Jones

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Wave action along the shores of Lima Reservoir in Centennial Valley, Montana is actively eroding the southern margins of three neighboring Paleoindian sites. Despite ostensible similarity among the sites, major site formation differences are apparent in exposed sediments. Shoreline cutbank exposures one-to-five meters high connect the sites and reveal a complicated geomorphic history. Although each site contains artifact evidence of terminal Pleistocene-early Holocene occupations, Paleoindian components at these three localities occur in very different contexts: one is buried, while the other two are apparent surface scatters. This raise the question of why sites of the same age are in both …

Comparative, Lithology-Based Biogeography Of Phreatophytic And Non-Phreatophytic Matrices Along A North-South Gradient Of The South Texas Sand Sheet, Christopher Joaquin Munoz

Theses and Dissertations

A 70km-long, N-S stratigraphic cross-section spanning the entirety of the South Texas Sand Sheet (STSS) has been rendered along Texas Interstate 69C. The cross-section indicates localized zones of substantial STSS thickness (>4m) as well as zones where the underlying Goliad Formation is either exposed or just below the surface (<0.5m). Spatial patterns of both phreatophytic and non-phreatophytic vegetation assemblages were analyzed by means of remote sensing and in situ herbaceous species evaluations. Biogeographic patterns were comprised of three vegetation matrices: P. glandulosa-dominated, Q. virginiana-dominated and a matrix of herbaceous plants. The geographic distribution of vegetation assemblages corresponded to specific lithological parameters and features. Namely, Q. virginiana concentration exhibited a positive linear relationship with the lithological parameter of STSS thickness (P =2.122x10-11) (α = 0.05). P. glandulosa/V. farnesiana …

Facies And Diagenesis Analyses Of The Fort Terrett Formation Of The Lower Cretaceous Edwards Group, Near Junction, Texas, Richard Alden Urwin Jr.

Electronic Theses and Dissertations

The Fort Terrett Formation was deposited on the western edge of the Comanche Shelf in central Texas. The predominate lithology of the Fort Terrett Formation is limestone which caps the hills that surround Junction, Texas. Deposition of the Fort Terrett Formation occurred within shallow, quiet waters during the Lower Cretaceous. Rose (1974) developed a general stratigraphic correlation and lithostratigraphic framework for the Cretaceous Shelf and established a regional correlation. Four stratigraphic divisions have been recognized in the Fort Terrett Formation. These are: a basal nodular unit, a burrowed unit, a dolomitic unit, and the Kirschberg evaporites. Wilkerson (2018) provided the …

Stratigraphy And Depositional Characterization Of The Moorefield Shale (Middle-Late Mississippian) In Its Type Area, Northeastern Arkansas (Eastern Arkoma Basin), Griffin Warner

Graduate Theses and Dissertations

The Moorefield Shale represents the Meramecian Series in the Eastern Arkoma Basin in northern Arkansas. Lying on the margin of the Mississippi Embayment and Reelfoot Rift, sequence stratigraphic interpretations have labelled the Moorefield Shale a lowstand wedge succeeding the Early Mississippian (Osagean) Boone Limestone conformably and overlain conformably by the Hindsville Limestone/Batesville Sandstone. The unit contains a basal brown-black limestone and succeeding brown-black phosphatic shale. The Moorefield Shale was deposited along the broad, stable cratonic platform on the southern flank of Laurasia, before it’s collision with Gondwanaland to form the supercontinent Pangea at the end of the Paleozoic. During this …

Volcanic Stratigraphy And Age Model Of The Kimama Deep Borehole (Project Hotspot): Evidence For 5.8 Million Years Of Continuous Basalt Volcanism, Central Snake River Plain, Idaho, Katherine E. Potter, Duane E. Champion, Robert A. Duncan, John W. Shervais

Geosciences Faculty Publications

The Snake River Plain of central Idaho represents the world’s best example of a mantle hotspot track impinging upon continental crust and provides a record of bimodal volcanism extending over 12 Ma to the present. Project Hotspot recovered almost 2 km of continuous drill core from the Kimama borehole, located in central Idaho on the axial volcanic zone. The Kimama drill core represents the most complete record of mafic volcanism along the Yellowstone–Snake River Plain hotspot track.

A total of 432 basalt flow units, representing 183 basalt flows, 78 basalt flow groups, and 34 super groups, along with 42 sediment …

Mississippian-Devonian Black Shales Of Kentucky: East-West Transect In Five Cores From The Appalachian Basin To The Illinois Basin, Patrick J. Gooding, Frank R. Ettensohn

Map and Chart--KGS

Devonian-Mississippian black shales are widespread across North America and underlie nearly 70 percent of Kentucky (Kepferle and Roen, 1981; Ettensohn and others, 1988). These black-shale units are among the most thoroughly investigated format ions in the commonwealth, because t hey have sourced most of t he conventional hydrocarbons (Gooding and Ettensohn, 2008; Gooding, 2013), have been major producers of gas in both the Illinois and Appalachian Basins, and have major potential as unconventional producers in both basins. In fact, maturation indicators such as vitrinite reflectance and total organic carbon, from both basins, show that the shales are most ly mature …

Deep Structure Of Central Menderes Massif: Data From Deep Geothermal Wells, Fatma Gülmez, Emre Damci, Umut Bariş Ülgen, Aral Okay

Turkish Journal of Earth Sciences

The Menderes Massif is a major Alpide metamorphic complex in western Turkey; it is subdivided into southern, central, and northern submassifs by the east-west trending grabens. The basement of the southern Menderes Massif consists of Neoproterozoic micaschists (Selimiye Formation) intruded by Neoproterozoic granites. The basement is overlain by Permo-Carboniferous phyllite, marble, and quartzite (Göktepe Formation), which pass up into a thick sequence of Mesozoic marbles with emery horizons (Milas Marble). The marbles are overlain by latest Cretaceous recrystallized pelagic limestone and Paleocene metaclastics, which are thrusted over by the Lycian nappes. The metamorphism and deformation of the Phanerozoic sequence of …

Stratigraphic Response Of The Differential Rise Of The Gypsum Valley Salt Wall, Jurassic Entrada Formation, Paradox Basin, Colorado, Rafael Andres Delfin

Open Access Theses & Dissertations

The effect of halokinetic processes on fluvial and marine depositional environments adjacent to salt diapirs have been well established through extensive research, however eolian systems in similar geologic settings have not been documented. This has left a void in our understanding of eolian depositional environments adjacent to salt diapirs. This study is aimed at providing new knowledge and a solid foundation on eolian systems and diapiric processes. Despite our limited understanding of theses interactions, there has been a recent interest in deep water prospectively in the Gulf of Mexico. Successful tests of the Norphlet Formation prove that eolian sandstones deposited …

Subsurface Stratigraphic Interpretation Of The Lower Atoka Formation, Northern Arkoma Basin, Arkansas, William Stephen Denham

Graduate Theses and Dissertations

The Arkoma Basin is a Carboniferous peripheral foreland basin creating a structural depression covering an approximate area of 33,800 miles2 that extends through east-central Oklahoma and west-central Arkansas. The entire basin fill includes Pre-Mississippian carbonate shelf deposits, Mississippian marine carbonates and black shales, and Pennsylvanian mixed carbonated/clastic and shore zone/deltaic deposits. The Lower Atoka formation (Pennsylvanian) occurs in outcrop along the southern Boston Mountain Plateau in northern Arkansas and extends into the subsurface of the Arkoma Basin over an area of 2,300 miles2. The Lower Atoka ranges from 600 to 1500 feet in thickness and represents a cyclic succession of …

The Occurrence Of The Greta Sandstone, Frio Formation (Late Oligocene), Texas Gulf Coastal Plain, Sean C. Kincade

Graduate Theses and Dissertations

The Greta sandstone is an informal lithostratigraphic unit of the upper Frio Formation (Oligocene) that occurs across the Texas Gulf Coastal Plain. The Greta sandstone has been known to geologists since it was first drilled in the 1930’s, yet there has been very little research into this un-depleted and overlooked reservoir. This study provides insights into the lateral distribution and reservoir facies of the Greta sandstone. The unit represents an aggradational to transgressive barrier sandstone package grading up to mud-rich open marine inner shelf deposits. The interval is easily recognizable in well logs based on its strong SP and Gamma-ray …

Stratigraphic Evaluation Of The St. Joe-Boone Boundary Interval, Kinderhookian-Osagean Series, Lower Mississippian System, Tri-State Region, Southern Midcontinent, Forrest Dalton Mcfarlin

Graduate Theses and Dissertations

The Lower Mississippian interval comprises a single, third-order, eustatic cycle subdivided lithostratigraphically into the St. Joe Limestone (Hopkins 1893) and overlying Boone Formation (Branner 1891, Simonds 1891) with type areas in northern Arkansas. Coeval, homotaxial limestones occur in adjacent southwestern Missouri and northeastern Oklahoma. Missouri formation names for the St. Joe interval are recognized in Arkansas as members (ascending order): Bachelor, Compton, Northview, Pierson. The Boone interval in Missouri is represented by the (ascending order): Reeds Spring, Elsey, Burlington-Keokuk undifferentiated, but utilization of those names in Arkansas is problematic. in northern Arkansas, the Boone Formation is subdivided into informal lower …

Petrographic And Stratigraphic Analysis Along The Lower Cretaceous Strata, In Kimble County Texas, Austin C. Wilkerson

Electronic Theses and Dissertations

The upper Trinity Group is predominantly a carbonate system with minor clastic couplets that were deposited during the Middle Cretaceous in the south Llano Uplift region. The upper Trinity Group was deposited on a southward dipping platform in the Kimble County area. Stratigraphic units of the upper Trinity Group are the Hensel Formation, determined to be supratidal claystones, the Glen Rose Formation, which are mudstones that were deposited in a carbonate lagoon, and the Walnut and Fort Terrett formations, which are wackestones to packstones interpreted to have been deposited on a shallow carbonate shelf.

Nine stratigraphic sections were measured along …

Regional Stratigraphy And Distribution Of The Coastal Group, St. Elizabeth Parish, Southwestern Jamaica, Brett M. Kenning

Graduate Theses/Dissertations

This contribution examines the characteristics and ages of sedimentary units in the Coastal Group located along the southwestern Jamaica coast between Great Pedro Bluff and Fort Charles Bay in southwestern St. Elizabeth Parish. The coastline is characterized by laterally discontinuous low cliff exposures, separated by modern beach deposits and tectonically raised shore platforms composed of the White Limestone Group (mid-Eocene to mid-Miocene) and coral rudstone to floatstone and calcareous sandstone of the Coastal Group (late Pleistocene). Electron-Spin Resonance spectroscopy conducted on corals collected from a coral rudstone to floatstone facies yielded an estimated age of 120 ka. The coral facies …

Stratigraphic Reconstruction Of A Late Pleistocene Bald Cypress Forest Discovered On The Northern Gulf Of Mexico Continental Shelf, Suyapa Michell Gonzalez Rodriguez

LSU Master's Theses

A previously buried bald cypress forest (Taxodium distichum) was discovered on the continental shelf, offshore of Orange Beach, Alabama, USA, in ~20 m water depth. The forest was exhumed by Hurricane Ivan in 2004, and is now exposed as stumps in life position in a trough located in the northern Gulf of Mexico continental shelf seafloor. We are investigating the local stratigraphy, paleo-landscape, and mode of forest preservation of this unique site. In August 2015 and July 2016, submersible vibracores (18 in total) were collected. Core analysis included: bulk density and imaging via Geotek multi sensor core logger, …

Understanding The Late Mesoproterozoic Earth System From The Oldest Strata In Grand Canyon: C-Isotope Stratigraphy And Facies Analysis Of The 1254 Ma Bass Formation, Grand Canyon Supergroup, Az., Usa, Erin C. Lathrop

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Rocks provide insight into ancient times before complex animals existed. The oldest sedimentary rocks in Grand Canyon (the Bass Formation) allow us to glimpse into what things might have been like over a billion years ago. These rocks record the time known as the Mesoproterozoic Era (1.6 to 1.0 billion years ago), otherwise known as the ‘boring billion’. These rocks are thought to be the right age to indicate the end of an oddly stable world when continents were quiet and life was calm, yet they predate younger rocks that record extreme events. The Bass Formation, some of the only …

Early Pliocene Molluscs From The Easternmost Mediterranean Region (Se Turkey): Biostratigraphic, Ecostratigraphic, And Palaeobiogeographic Implications, Yeşi̇m Büyükmeri̇ç, Erdoğan Teki̇n, Erdal İbrahi̇m Herece, Koray Sözeri̇, Ni̇hal Akca, Baki̇ Erdoğan Varol

Turkish Journal of Earth Sciences

The mollusc faunas from Pliocene deposits of the Hatay-İskenderun region were investigated at nine localities and complemented with three localities from earlier studies. The Pliocene units were deposited in three adjacent subbasins, Hatay-Samandağ (HS), Altınözü-Babatorun (AB), and İskenderun-Arsuz (İA); the first two are also known as the Hatay Graben. Basin configurations and shape, environmental evolution, and faunal compositions were affected by differential tectonic histories since the Late Miocene. In total 162 species (94 gastropod, 61 bivalve, and 7 scaphopod) are recorded, 80 of which are recorded for the first time from the region. The occurrence of tropical stenohaline benthic taxa …

Stratigraphy And Organic Geochemistry Reveal Patterns Of Late Quaternary Paleo-Productivity At Mono Lake, California, Bailee Nicole Hodelka

Theses and Dissertations--Earth and Environmental Sciences

Mono Lake (CA) is a hydrologically closed lacustrine basin well-known for its paleo-shorelines, which record fluctuations in water level for the last deglacial and late Holocene. Mono Lake is a sentinel of California’s water supply, situated in the rain shadow of the Sierra Nevada, a mountain range whose snowpack is a vital source of freshwater for urban and agricultural districts to the west and south. Recent droughts, floods, and wildfires show that California is threatened by climate change, but how these changes impact and get recorded by Mono Lake sediments remains poorly known. Here, we use a new radiocarbon-dated deepwater …

Paleozoic Sandstones In The Tri-State Region, Southern Ozarks: Tectono-Stratigraphic Sequence Development And Compositional Evolution, The Source And Delivery Conundrum, And The Regional Tectonic History, Elvis Chekwube Bello

Graduate Theses and Dissertations

The Paleozoic stratigraphic record of the Ozark Region, southern midcontinent has been divided into at least 33 formations, with the most significant thickness of 9692 feet preserved in northwest Arkansas. The potential thickness would have been much greater, but epeirogenic movements and sea-level rise and fall produced regional surfaces of erosion reducing the record. That interplay between tectonics (epeirogenic movements) and eustatic change (transgressive-regressive cycles) preserved in the Ozark sedimentary history provides the basis for recognition of five distinct, but related, tectonostratigraphic units designated TS 1 through TS 5: Late Precambrian-Middle Cambrian (TS 1), Late Cambrian-Earliest Ordovician (TS 2), Early …

Geologic Mapping Of The Vernal Nw Quadrangle, Uintah County, Ut, And Stratigraphic Relationships Of The Duchesne River Formation And Bishop Conglomerate, Casey Andrew Webb

Theses and Dissertations

Detailed mapping (1:24,000), measured sections, and clast counts in conglomerates of the Duchesne River Formation and Bishop Conglomerate in the Vernal NW quadrangle in northeastern Utah reveal the middle Cenozoic stratigraphic geometry, the uplift and unroofing history of the eastern Uinta Mountains, and give evidence for the pulsed termination of Laramide uplift. The Unita Mountains are an EW-trending reverse fault bounded and basement-cored, Laramide uplift. The oldest unit of the Duchesne River Formation, the Eocene Brennan Basin Member, contains 80-90% Paleozoic clasts and <20% Precambrian clasts. Proximal to the Uinta uplift the conglomerates of this member are dominated by Paleozoic Madison Limestone clasts (70-90% of all clasts). Farther out into the basin, Paleozoic clasts still dominate in Brennan Basin Member conglomerates, but chert clasts are more abundant (up to 43%) showing the efficiency of erosion of the carbonate clasts over a short distance (~5 km). Conglomerates in the progressively younger Dry Gulch Creek, Lapoint, and Starr Flat members show a significant upward increase in Precambrian clasts with 34-73% Uinta Mountain Group and 8-63% Madison Limestone. Duchesne River Formation has a significant increase in coarse-grained deposits from the southern parts of the quadrangle (20-50% coarse) to the northern parts (75% coarse) nearer the Uinta uplift. The lower part of the Duchesne River Formation exhibits a fining upward sequence representing a tectonic lull. Clast count patterns show that pebbly channel deposits in the south maintain similar compositions to their alluvial fan counterparts. To the north, the fine-grained Lapoint and Dry Gulch Creek members of the Duchesne River Formation appear to pinch out completely. This can be explained by erosion of these fine-grained deposits or by lateral facies shifts before deposition of the next unit. Starr Flat Member conglomerates were deposited above Lapoint Member siltstones and represent southward progradation of alluvial fans away from the uplifting mountain front. Similarities in composition and sedimentary structures have caused confusion surrounding the contact between the Starr Flat Member and the overlying Bishop Conglomerate. Within the Vernal NW quadrangle, we interpret this contact as an angular unconformity (the Gilbert Peak Erosion Surface) developed on the uppermost tilted red siltstone of the Starr Flat Member sometime after 37.9 Ma. Stratigraphic and structural relationships reveal important details about the development of a Laramide mountain range: 1) sequential unroofing sequences in the Duchesne River Formation, 2) progradation of alluvial fans to form the Starr Flat Member, 3) and the unconformable nature of the Gilbert Peak Erosion Surface lead to the conclusion that there were at least 3 distinct episodes of uplift during the deposition of these formations. The last uplift episode upwarped the Starr Flat Member constraining the termination of Laramide uplift in the Uinta Mountains to be after deposition of the Starr Flat Member and prior to deposition of the horizontal Bishop Conglomerate starting at about 34 Ma. This, combined with ⁴⁰Ar/³⁹Ar ages of 39.4 Ma from the Dry Gulch Creek and Lapoint member, show …

Stratigraphy Of The Middle Cambrian Lincoln Peak Formation And Evolution Of The House Range Embayment, Eastern Nevada, Ibrahim Zallum

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

This study examined the Middle Cambrian (c. 500 MA) Lincoln Peak Formation and Patterson Pass Shale. The initial goal was to create a stratigraphic model for these units. This model was then compared to those from already studied units in western Utah, which combined with the Nevada units form the rock record of an ancient feature known as the House Range Embayment, which was an area of greater water depth superimposed on the continental shelf. This study found that the Nevada units exhibit a series of depositional sequences similar to those in western Utah, but at a lower resolution. This …